EX unit five: solids, liquids and gases Flashcards
density =
mass / volume
what is the symbol for density
ρ
what is the symbol for volume
V
what is density measured in
kg/m cubed or g/cm cubed
how do you convert from g/cm cubed to kg/m cubed
multiply by 1000
how do you measure volume (solid)
measure width (w), height (h), and depth (d) and multiply together.
how do you measure mass (solid)
use an electronic balance
how do you measure mass (liquid)
put a measuring cylinder on the electronic balance, zero it, and pour in the liquid.
how do you measure volume (liquid)
pour the liquid in a measuring cylinder. it may be callibrated in ml: 1ml = 1cm cubed.
pressure =
force / area
whats the symbol for area
A
what is pressure measured in
pascals (Pa)
what is pressure
weight in newtons per metre squared acting down on a surface.
1 Pa =
1 N/m squared
pressure difference =
height x density x gravitational field strength
what is the symbol for PRESSURE difference
p
process of solid to liquid
melting
process of liquid to gas
boiling
process of gas to liquid
condensation
process of liquid to solid
freezing
what is a boiling point
when a liquid becomes a gas
what is a melting/freezing point
when solid becomes a liquid
describe the structure and position of molecules in a solid substance
the molecules in a solid are tightly packed and held in fixed positions by strong forces. the molecules can vibrate around their fixed positions. as the solid gets hotter the vibrations get bigger.
describe the structure and position of molecules in a liquid substance
closely packed
irregular structure
intermolecular forces are strong molecules move randomly.
describe the structure and position of molecules in a gas substance
widely spaced
continuous state of random motion
weak intermolecular forces except during collisions
molecules move randomly.
what is specific heat capacity
the amount of energy required to increase the temperature of 1 kilogram of a certain substance by 1 degree celsius.
what is the unit for specific heat capacity
J/kg degrees celsius
what is the symbol for specific heat capacity
c
heat change =
mass x specific heat capacity x temperature change
what is the symbol for heat change
ΔQ
what is the symbol for temperature change
ΔT
1st gas law: the random motion of gas and liquid particles explains why…
pressure acts in all directions at any point
2nd gas law: the speed of molecules increases with temperature, so as we heat gases in a rigid container, more…
energetic collisions with the walls happen more frequently, raising the pressure of the gas.
3rd gas law: the temperature of a gas in Kelvin is proportional to…
the average kinetic energy of the gas molecules
what is Boyle’s law
that volume is inversely proportional to pressure.
p1 x V1 =
p2 x V2
p1/p2 =
V2/V1
what is absolute zero
when you cool a fixed mass of gas at constant volume, its pressure drops. if you continue to cool the gas below 0 degrees celsius, the pressure will keep dropping until the pressure is zero, and graphs predict that this will happen when the temperature is -273 degrees celsius, and this is the lowest possible temperature. this is called 0 Kelvin (K).
how do you convert celsius to kelvin
add 273
how do you convert kelvin to celsius
subtract 273
p1/T1 =
p2/T2
what does the pressure law mean
if you double the kelvin temperature of gas in a rigid container the pressure of the gas doubles.